<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
    <meta name="author" content="李愧愧">
    <title></title>
    <style>
        ul{
            padding: 0;
            margin: 0;
            list-style: none;
        }
        li{
            float: left;
        }
        .box{
            width: 340px;
            height: 430px;
            margin: 0 auto;
            background-color: burlywood;
        }
        ul li{
            width: 75px;
            height: 75px;
            margin: 5px;
            border-radius: 5px;
        }
        ul li img{
            width: 100%;
            height: 100%;
            border-radius: 5px;

        }
        .bg{
            float: left;
            width: 230px;
            height: 230px;
            margin: 12px;
            margin-right: 13px;
        }
        .bg img{
            width: 100%;
            height: 100%;
        }
    </style>
</head>
<body>
    <div class="box">
        <ul>
            <div class="bg"><img src="./img/big_1.jpg" alt=""></div>
            <li><img src="./img/big_1.jpg" alt=""></li>
            <li><img src="./img/big_2.jpg" alt=""></li>
            <li><img src="./img/big_3.jpg" alt=""></li>
            <li><img src="./img/big_4.jpg" alt=""></li>
            <li><img src="./img/big_5.jpg" alt=""></li>
            <li><img src="./img/big_6.jpg" alt=""></li>
            <li><img src="./img/big_7.jpg" alt=""></li>
            <li><img src="./img/big_8.jpg" alt=""></li>
            <li><img src="./img/big_9.jpg" alt=""></li>
            <li><img src="./img/big_10.jpg" alt=""></li>
            <li><img src="./img/big_11.jpg" alt=""></li>
        </ul>
    </div>

<script>
    var lis = document.querySelectorAll('li');
    var img = document.querySelectorAll('img');
    // var bg = document.querySelector('.bg');
    for(var i=1;i<lis.length;i++){
        lis[i].index = i;
        lis[i].onmousemove =function(){
            console.dir(this);
            // for(var j=0;j< img.length;j++){
                img[0].src =img[this.index].src;
                console.dir('img[o].src')
            // }
        }
    }
</script>
</body>
</html>